IX THE HISTORY AND SCOPE OF ZOOLOGY 291 



Biology, Botany and Zoology, were actually limited 

 to the accumulation of observations, which were noted, 

 tabulated, and contemplated by the students of these 

 subjects with wonder and delight, but only to a limited 

 extent and in restricted classes of facts with any hope 

 or intention of connecting the phenomena observed 

 with the great nexus of physical sequence or causa- 

 tion. A vague desire to assign the forms and the 

 activities of living things in all their variety to general 

 causes has always been present to thoughtful men 

 from the earliest times of which we have record, but 

 the earlier attempts in this direction were fantastic in 

 the extreme ; and it is the mere truth that, at the 

 time when the phenomena of inorganic nature had 

 been recognised as the outcome of uniform and con- 

 stant properties capable of analysis and measurement, 

 living things were still left hopelessly out of the 

 domain of explanation, the earlier theories having been 

 rejected and nothing as yet suggested in their place. 



The history of Zoology as a science is therefore the 

 history of the great biological doctrine of the evolution 

 of living things by the natural selection of varieties 

 in the struggle for existence, since that doctrine is 

 the one medium whereby all the phenomena of life, 

 whether .of form or function, are rendered capable of 

 explanation by the laws of physics and chemistry, 

 and so made the subject-matter of a true science or 

 study of causes. A history of Zoology must take 

 account of the growth of those various kinds of infor- 

 mation with regard to animal life which have been 

 arrived at in past ages through the labours of a long 



